1. Field of the Invention
The invention relates generally to digital cameras and, more specifically, to a system and method for charging rechargeable batteries in a digital camera.
2. Description of the Related Art
Digital camera technology has developed rapidly over the past decade. A broad variety of digital cameras are now available to meet the diverse needs of a wide spectrum of consumers. A conventional digital camera provides a user with the ability to capture and to store digital images and/or digital video electronically. Digital cameras may be powered by non-rechargeable batteries or, alternatively, by rechargeable batteries, such as Nickel-Metal Hydride (NiMH) batteries, Nickel-Cadmium (NiCAD) batteries, Lithium Polymer (Li-Poly) batteries, or Lithium-ion (Li-ion) batteries.
A digital camera powered by non-rechargeable batteries eventually exhausts the charge provided by the batteries and then requires replacement batteries to continue operating. The user of the digital camera is thus required to repeatedly purchase non-rechargeable batteries in order to provide further power to the digital camera. For this reason, some digital cameras are powered by rechargeable batteries.
A digital camera powered by rechargeable batteries eventually exhausts the charge provided by the rechargeable batteries, and the batteries can then be recharged to provide further power to the digital camera. With such designs, either an external charger or a charger internal to the camera may be implemented to recharge the rechargeable batteries.
When an external charger is implemented, the external charger is connected to a standard wall outlet or to a universal serial bus (USB) port on a personal computer (PC) for recharging purposes. For example, with digital cameras that are powered by rechargeable NiMH batteries and require an external charger, once the charge supplied by the rechargeable NiMH batteries is exhausted, the user typically has to remove the NiMH batteries from the digital camera and then load the NiMH batteries into the external charger. The external charger has to then be connected to either a standard wall outlet or to a USB port on a PC to recharge the NiMH batteries. However, if the user does not have access to a standard wall outlet or to a PC, or if the user does not have the external charger or any required cabling, the NiMH batteries cannot be recharged.
When an internal charger is implemented, the digital camera is usually coupled to an A/C transformer, which is then connected directly to a standard wall outlet for recharging purposes, or to a USB port on a PC or other power source. For example, with digital cameras that are powered by Li-ion batteries and have internal chargers, once the charge supplied by the rechargeable Li-ion batteries is exhausted, in some instances the user has to connect the digital camera to an A/C transformer and then connect the A/C transformer to a standard wall outlet to recharge the Li-ion batteries. In other instances, the user has to connect the digital camera to the USB port of a computer or other power source to recharge the batteries. In either case, if the user does not have access to a standard wall outlet, or if the user does not have the A/C transformer or any required cabling, the Li-ion batteries cannot be recharged and the camera will no longer function.
In an attempt to overcome some of the drawbacks of digital cameras powered only by rechargeable batteries, some digital cameras have been designed to be powered by either rechargeable batteries or non-rechargeable batteries. With such designs, however, the non-rechargeable batteries still have to be replaced, the user of the digital camera still has to have access to a standard wall outlet to recharge the rechargeable batteries, or the batteries must be removed from the digital camera in order to be charged from an A/C or USB power source. Further, as described above, a user typically also has to have access to either an external charger (and required cabling) or an A/C transformer in order to charge the rechargeable batteries.
As the foregoing illustrates, what is needed in the art is a digital camera that operates on both rechargeable and non-rechargeable batteries and implements a more user-friendly charging technique than those set forth above.